From JP 08075674A a device is known for recognizing foreign bodies in a transparent container which is already filled and closed, where light sources which are located laterally next to the bottom of the container illuminate the container and a camera which is arranged below the bottom of the bottle records the light which is reflected by the foreign bodies.
A drawback of such a known device is that the camera not only acquires the transparent bottom of a container, but the entire container from inside, resulting in strong contrast differences in the image area. Consequently, an electronic evaluation of the images, which is usually based on differences in brightness, is made difficult.